风向变化对城市大气污染的影响及试验分析

针对城市大气污染的复杂多变状况，在理论分析的基础上，通过风洞实验对城市大气污染扩散模型进行了模拟试验研究，建立了适合一定条件下城市大气污染物扩散的数学和物理模型，并对城市大气污染状况的影响因素进行了分析，在得到特定条件下城市大气污染扩散普遍规律的同时，重点讨论了风向变化对城市大气污染的影响，该方法同时还可以应用于城市大气污染物扩散浓度的估算。     

酸雨对种子萌发影响的实验研究

采用ＰＨ值２．５、３．０、３．５、４．５的酸雨处理小麦种子，观察种子的萌发率、平均萌发天数和萌发势。结果表明：酸雨对种子的萌发率和平均萌发无显著影响，但对种子萌发势有显著影响。     

环境中二噁(口英)及其检测技术进展

从二(?)(?)类化合物的结构、来源、毒性等简要说明对其监测的必要性,且从仪器监测(包括气相色谱、气质联用、串联质谱等)和生物监测(包括利用指示生物、生物标志物等)概述了80年代以来国内外对二(?)(?)类物质尤其是几种极毒性化合物如多氯代二苯二(?)(?)(PCDDs)和多氯代二苯呋喃(PCDFs)等化合物的检测技术成果。     

铁路环境噪声对居民冲击影响的模糊综合评价

铁路环境噪声对居民的冲击影响程度不仅与列车运行辐射噪声级有关，而且还与人口密度，及白天、夜间的人口比例等因素有关。考虑以上诸多因素，采用模糊综合评价方法进行铁路环境噪声对居民的冲击影响的综合比较评价，并通过实例验证了该方法的有效性和可靠性，为铁路环境噪声评价提供了新的方法。     

麻石文丘里洗涤吸收器在APV尾气处理上的应用

介绍了ＡＰＶ喷雾干燥尾气的性质，原尾气系统存在的问题，改造中采取的措施、原理、流程和取得的效果。实践证明，用“麻石文丘里一次降温、洗涤—ＸＰ型塔板二次洗涤—旋流除雾器除雾”的改造方案，取代原“换热器降温—喷淋塔洗涤—折流脱水器脱水”的流程，取得了良好的降温、洗气和除雾效果，且工程费用低。     

污水处理的节能实践

采用变频技术时污水处理设备进行节能改造，使其根据污水水量、水质的变化而自动调速。将污泥机械脱水滤液与剩余污泥混合，以此来改善污泥的浓缩脱水性能。工程运行实例表明：设备的变频调速和滤液的再利用能够降低污水处理的能量消耗，提高工艺运行水平。     

Carbon isotope ratios in logged and unlogged boreal forests: Examination of the potential for determining wildlife habitat use

Due to assimilation of recycled CO₂ from litter decomposition and photosynthetic changes in carbon fractionation at low light levels, the foliage at the base of a forest is often more depleted in¹³C compared to that exposed to the atmosphere in either the canopy or in open clearings. This is referred to as the canopy effect. African research has indicated that these habitat differences in foliar ¹³C can be substantial enough to affect the carbon isotope ratios of resident fauna. Previous work documenting a 30-year chronology on moose teeth from Isle Royale National Park indicated a progressive depletion in¹³C and suggested that this could be due to forest regrowth following extensive burning. The present study examined the assumption implicit in this hypothesis that foliar ¹³C varies between open and closed boreal forest sites. I found a marginal canopy effect of 2 ¹³C difference between upper canopy and ground flora for a forest in northwestern Ontario and an average difference of 1.2 in under- and mid-story vegetation between closed forests and open clear-cuts. Because of these small differences, the utility of carbon isotope analysis in quantifying temporally integrated exploitation of deforested habitats will be low for northern boreal locations. In denser forests, such as those in the tropics or western North American where the canopy effect can be expected to be much greater, ¹³C analysis may still offer some promise for determining selection by wildlife of disturbed habitats.     

Enzymatic degradation of poly([R,S] β-hydroxybutyrate)

The synthetic analogue of a bacterially produced polyester, poly(-hydroxybutyrate) (PHB) was synthesized from racemic -butyrolactone using anin situ trimethyl aluminum-water catalyst. The polymer was fractionated into samples differing in molecular weight and isotactic diad content. The latter was closely related to degree of crystallinity. The biodegradation of these fractions were examined by monitoring mass loss over time in the presence of anAlcaligenes faecalis T1 extracellular bacterial poly(-hydroxybutyrate) depolymerase. The fraction with high isotactic diad tacticity content showed little or no degradation over a 50 hour incubation period, whereas the fraction of intermediate isotactic diad content degraded in a continuous steady fashion at a rate that was less than that for bacterial PHB. The low isotactic diad fraction underwent a rapid initial degradation, followed by no further mass loss. The presence of stereoblocks in the polymer structure of the various fractions was an influence on the degree of susceptibility towards degradation and is related to sample crystallinity.     

我国矿产资源的现状及保护对策

本文着重讲述了我国矿产资源的特点,全面分析了我国矿产资源的现状,并 提出缓解矿产资源危机的一些对策。     

Genetically Modified (GM) Crops: Precautionary Science and Conflicts of Interests

Risk governance of GM plants and GMfood products is presently subject to heatedscientific and public controversies. Scientistsand representatives of the biotechnologyindustry have dominated debates concerningsafety issues. The public is suspicious withregard to the motives of scientists, companies,and political institutions involved. Thedilemmas posed are nested, embracing valuequestions, scientific uncertainty, andcontextual issues. The obvious lack of data andinsufficient information concerning ecologicaleffects call for application of thePrecautionary Principle (PP). There are,however, divergent opinions among scientistsabout the relevance of putative hazards,definition of potential ``adverse effects,' andwhether actions should be taken to preventharm. The reliance on the concept ofsubstantial equivalence in safety evaluation ofGM food is equally controversial. Consequently,value assumptions embedded in a scientificframework may be a barrier for employment ofthe PP. One of our major conclusions is thatprecautionary GMP usage requires riskassessment criteria yet undeveloped, as well asbroader and more long-term conceptions of risk,uncertainty, and ignorance. Conflicts ofinterest and public participation are otherissues that need to be taken intoconsideration. GMP governance regimes that arejustifiable from a precautionary and ethicalpoint of view must transcend traditionalscientific boundaries to include alternativescientific perspectives as well as publicinvolvement.